IEEE 1394 TRANSMITTER, IEEE 1394 RECEIVER and AUDIO DATA CONTENT TRANSMISSION METHOD

ABSTRACT

There is provided an IEEE 1394 transmitter for transmitting a plurality of audio data contents, having an audio data generator configured to sample the plurality of audio data contents sequentially to generate format data of an audio data content; and an IEEE 1394 transmission controller configured to add an IEEE 1394 header packet to the format data of the audio data content.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromJapanese Patent Application No. 2007-066687 filed on Mar. 15, 2007, theentire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The application relates to an IEEE (Institute of Electrical andElectronics Engineers) 1394 transmitter.

2. Description of the Related Art

Japanese Laid-open Patent Publication No. 2005-025270 discloses atechnique for transmitting and receiving content using the IEEE 1394standard.

SUMMARY

According to an aspect of an embodiment of the present invention, thereis provided an IEEE 1394 transmitter for transmitting a plurality ofaudio data contents, comprising: an audio data generator configured tosample the plurality of audio data contents sequentially to generateformat data of an audio data content; and an IEEE 1394 transmissioncontroller configured to add an IEEE 1394 header packet to the formatdata of the audio data content.

The above-described embodiments of the present invention are intended asexamples, and all embodiments of the present invention are not limitedto including the features described above.

Additional advantages and novel features of the invention will be setforth in part in the description that follows, and in part will becomemore apparent to those skilled in the art upon examination of thefollowing or upon learning by practice of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing an IEEE 1394 transmitter;

FIG. 2 is a diagram showing an IEEE 1394 packet;

FIG. 3 is a diagram showing a structure of an isochronous packet (ISO1)of a first audio data content;

FIG. 4 is a diagram showing a structure of an isochronous packet (ISO2)of a second audio data content;

FIG. 5 is a diagram showing a structure of an isochronous packet (ISO3)of a third audio data content;

FIG. 6 is a block diagram showing an IEEE 1394 transmitter in accordancewith an embodiment of the present invention;

FIG. 7 is a diagram showing a standard AM824 data format in accordancewith an embodiment of the present invention;

FIG. 8 is a diagram showing a sub-label-attached AM824 data format inaccordance with an embodiment of the present invention;

FIG. 9 is a diagram showing audio data content of eight channels inaccordance with an embodiment of the present invention;

FIG. 10 is a timing chart of an encryption instruction signal ANGX inaccordance with an embodiment of the present invention;

FIG. 11 is a diagram showing an isochronous packet header format inaccordance with an embodiment of the present invention;

FIG. 12 is a diagram showing a CIP header format in accordance with anembodiment of the present invention;

FIG. 13 is a diagram showing an isochronous packet in accordance withthe first embodiment;

FIG. 14 is a diagram showing an IEEE 1394 packet in accordance with thefirst embodiment;

FIG. 15 is a block diagram of an IEEE 1394 receiver in accordance withan embodiment of the present invention; and

FIG. 16 is a flowchart showing a process for decrypting audio datacontent in accordance with an embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference may now be made in detail to embodiments of the presentinvention, examples of which are illustrated in the accompanyingdrawings, wherein like reference numerals refer to like elementsthroughout.

When audio data of a plurality of contents is transmitted using the IEEE1394 standard, for example, an IEEE 1394 packet is transmitted by anIEEE 1394 transmitter 100 shown in FIG. 1 using the IEC (InternationalElectrotechnical Commission) 61883-6 standard.

The IEEE 1394 transmitter 100 is configured to transmit three audio datacontents each having eight channels. A first audio data content inputfrom a three-wire interface is converted into parallel sampled audiodata by a first phase-locked loop (PLL) 101 and a first serial-parallelconverter, and is output to a first IEC 61883-6 encoder 104. The firstIEC 61883-6 encoder 104 attaches a label generated by a first labelgenerator 103 to the sampled audio data, and outputs the label-attachedsampled audio data to a first encryption unit 105. The first encryptionunit 105 encrypts the label-attached sampled audio data according to anoutput of an encryption controller 117. The encryption controller 117sets a level for encrypting the data to the first encryption unit 105 onthe basis of an encryption setting signal ANG input from outside.

Second and third audio data contents are also processed in a similarmanner. The resulting first, second, and third audio data contents areinput to a selector 116. The selector 116 selects one of the first tothird audio contents, and outputs the selected content to an IEEE 1394packet generator 118. The IEEE 1394 packet generator 118 attaches aheader to data of each of the first to third audio contents, andtransmits an IEEE 1394 packet to the outside.

FIGS. 2 to 5 show an example in which a first audio data content of fourchannels, a second audio data content of two channels, and a third audiodata content of two channels are transmitted by IEEE 1394 packettransmission. As shown in FIG. 2, an IEEE 1394 packet includes a cyclestart packet (CS), an isochronous packet ISO1 of the first audio datacontent shown in FIG. 3, an isochronous packet ISO2 of the second audiodata content shown in FIG. 4, and an isochronous packet ISO3 of thethird audio data content shown in FIG. 5. Each of the packets ISO1 toISO3 has an isochronous header and a common isochronous packet (CIP)header attached to the top thereof. Therefore, the IEEE 1394 transmitter100 transmits an IEEE 1394 packet in which the isochronous header andthe CIP header are attached to data of each audio data content.

However, when audio data contents of a plurality of channels aretransmitted and received via an IEEE 1394 interface, a header isattached to each of the audio data contents. As a result, an overhead ofan IEEE 1394 packet increases. Therefore, it is desirable to reduce theoverhead of a packet when audio contents of a plurality of channels aretransmitted and received via an IEEE 1394 interface.

FIG. 6 is a block diagram of an IEEE 1394 transmitter 1 according to afirst embodiment of the present invention. The IEEE 1394 transmitter 1converts up to 24 audio data contents input via a three-wire interfaceinto an IEEE 1394 packet, encrypts the packet according to setting, andtransmits the encrypted packet to an IEEE 1394 bus.

The IEEE 1394 transmitter 1 includes a serial-parallel converter 2, aPLL 3, an IEC 61883-6 encoder 4, a label generator 5, an encryption unit6, an IEEE 1394 transmission controller 7, an sy parameter setting unit8, and an encryption controller 9.

The serial-parallel converter 2 converts up to 24 audio data contentsinput via the three-wire interface into parallel sampled audio data.

The IEEE 1394 transmitter 100 shown in FIG. 1 includes three PLLs,namely, the first PLL 101, the second PLL 106 and the third PLL 111. TheIEEE 1394 transmitter 1 according to the first embodiment includes asingle PLL, namely, the PLL 3. The IEEE 1394 transmitter 1 can receiveaudio data contents using a common clock. Since only one PLL is requiredfor clock control in the IEEE 1394 transmitter 1, the number ofterminals of clocks can be reduce and a power consumption of the PLL canalso be reduced.

The IEC 61883-6 encoder 4 and the label generator 5 convert the sampledaudio data into audio data complying with the IEC 61883-6 format.

FIG. 7 shows a standard AM824 data format. The individual sampled audiodata is converted to the standard AM824 data format in the IEC 61883-6format by attaching a label. FIG. 8 shows a sub-label-attached AM824data format. In the sub-label-attached AM824 data format in the IEC61883-6 format, two labels, i.e., a label and a sub-label, are attachedto the top of data.

FIG. 9 shows audio data content of eight channels. The audio datacontent of eight channels is composed of two quadlets ofsub-label-attached AM824 data at the top thereof, followed by standardAM824 data for the eight channels. Ancillary Data included in thesub-label-attached AM824 data contains information relating to the audiodata content, such as compression information of the audio data content.

The encryption unit 6 encrypts the AM824 data output from the IEC61883-6 encoder 4 using the 5C-DTCP (5 Company Digital TransmissionContent Protection) protocol according to an encryption instructionsignal ANGX output from the encryption controller 9. The encryptioncontroller 9 outputs the encryption instruction signal ANGX on the basisof an encryption signal ANG input from outside.

FIG. 10 is a timing chart of the encryption instruction signal ANGXoutput from the encryption controller 9. The two sets of Ancillary Data(in FIG. 10, ANC1 and ANC2) placed at the top of the AM824 data areencrypted using a sy parameter with the highest restrictiveness. Thedata of channels to be encrypted (in FIG. 10, CH5 and CH6) is encryptedaccording to the encryption signal ANG.

The copy levels include, in ascending order of restrictiveness,copy-free, copy-one-generation, and copy-never. The sy parameter settingunit 8 sets the sy parameter to the highest-restrictiveness copy levelbased on the encryption instruction signal ANGX.

Specifically, when the encryption instruction signal ANGX includescopy-free only, the sy parameter is set to copy-free. When theencryption instruction signal ANGX includes copy-one-generation but doesnot include copy-never, the sy parameter is set to copy-one-generation.When the encryption instruction signal ANGX includes copy-never, the syparameter is set to copy-never. Accordingly, the sy parameter is set tothe highest-restrictiveness copy level based on the encryptioninstruction signal ANGX.

The IEEE 1394 transmission controller 7 attaches the isochronous headerand the CIP (Common Isochronous Packet) header to the top of the IEC61883-6 format data output from the encryption unit 6, and transmits anentire isochronous packet to the external IEEE 1394 bus.

FIG. 11 shows an isochronous packet header format. A “data_length”parameter indicates the number of bytes in the entire isochronouspacket. The “data_length” parameter is set to an arbitrary value. A“tag” parameter indicates that the packet contains the CIP header, andis set to a fixed value of 01. A “channel” parameter indicates a channelnumber used to identify the isochronous packet, and is set to anarbitrary value. A “tcode” parameter is a code indicating the type ofthe packet, and is set to value 1010 in the case of an isochronouspacket. An sy parameter contains copy information in the audio format.

FIG. 12 shows a CIP header format. A source-node-ID (SID) parameterindicates an ID of a source node that transmits the packet. The SIDparameter is set to an arbitrary value. A data-block-size (DBS)parameter indicates the size of one divided data block, and is set to anarbitrary value. A fraction-number (FN) parameter indicates the numberof data blocks into which one source packet is divided. Since the IEEE1394 transmitter 1 does not divide a source packet, the FN parameter isset to a fixed value of 00. A quadlet-padding-count (QPC) parameterindicates the number of quadlets added for the division (a quadletrepresents a data sequence of four bytes).

Since the IEEE 1394 transmitter 1 does not perform the division, the QPCparameter is set to a fixed value of 000. A source-packet-header (SPH)parameter indicates whether or not a source packet header has beenattached. Since the IEEE 1394 transmitter 1 does not attach a sourcepacket header, the SPH parameter is set to a fixed value of 0. An Rsvparameter is an extension region for future use.

In the IEEE 1394 transmitter 1, the Rsv parameter is set to a fixedvalue of 00. A data-block-continuity-counter (DBC) parameter indicates acontinuity counter value of a data block, and is incremented by +1 eachtime one data block is transmitted. A format (FMT) parameter indicates aformat type of data of the packet. Since the IEEE 1394 transmitter 1handles an audio and music format, the FMT parameter is set to a fixedvalue of 010000. A format-dependent-field (FDF) parameter is a fielddepending on format, and is set to an arbitrary value. A time stampvalue is set in an SYT parameter.

FIG. 13 shows a structure of an isochronous packet transmitted from theIEEE 1394 transmitter 1 according to the first embodiment. Theisochronous packet is composed of an isochronous packet header, a CIPheader, IEC 61883-6 data, and a CRC of the data. In the IEC 61883-6data, the data of channels 5 and 6 is encrypted data, and therefore, thelabel of the data of channels 5 and 6 has a value other than 4X(expressed in hexadecimal notation, the same applies to the followingdescription). The sub-label-attached AM824 format packet includingAncillary Data regarding channels 5 and 6 is also an encrypted packet.The sy parameter in the isochronous packet header is also set to thevalue corresponding to the level for encryption.

FIG. 14 shows an IEEE 1394 packet transmitted from the IEEE 1394transmitter 1 according to the first embodiment. The IEEE 1394 packet isgenerated by inserting a cycle start packet (CS) before the isochronouspacket structure (ISO) shown in FIG. 13, and is transmitted from theIEEE 1394 bus.

The IEEE 1394 transmitter 1 according to the first embodiment transmitsaudio data content of a plurality of channels through a single contentpacket. Therefore the IEEE 1394 transmitter 1 according to the firstembodiment can handle a packet having a single header portion, and theoverhead of the IEEE 1394 packet can be reduced.

FIG. 15 is a block diagram of an IEEE 1394 receiver 10 according to anembodiment of the present invention. The IEEE 1394 receiver 10 receivesa packet from an IEEE 1394 bus, and transmits audio content to outsidevia a three-wire interface.

The IEEE 1394 receiver 10 includes an IEEE 1394 reception controller 11,a first determination unit 12, a second determination unit 13, a firstdecryption unit 14, a third determination unit 15, a second decryptionunit 16, a selector 17, a decryption controller 18, an IEC 61883-6decoder 19, a PLL 20, and a parallel-serial converter 21.

The IEEE 1394 reception controller 11 reads, from the packet transmittedfrom the IEEE 1394 bus, the sy parameter included in the isochronouspacket header and the standard AM824 format data included in the IEC61883-6 data, including the data channels, quadlet-by-quadlet.

The first determination unit 12 determines the copy level of the syparameter, i.e., copy-free, copy-one-generation, or copy-never. Thedetermination result is output to the decryption controller 18.

The second determination unit 13 receives a label in a quadlet ofstandard AM824 format data including a data channel read by the IEEE1394 reception controller 11, and determines whether or not the labelhas a value of 4X. The determination result is output to the decryptioncontroller 18.

The first decryption unit 14 decrypts the quadlet of data read by theIEEE 1394 reception controller 11 using the sy parameter. The decrypteddata is output to an input terminal IN1 of the selector 17. The label inthe decrypted data is output to the third determination unit 15.

The third determination unit 15 receives the label in the AM824 formatdata decrypted by the first decryption unit 14, and determines whetheror not the label has a value of 4X. The determination result is outputto the decryption controller 18.

The second decryption unit 16 decrypts the quadlet of data read by theIEEE 1394 reception controller 11 using a parameter other than the syparameter. The decrypted result is output to an input terminal IN2 ofthe selector 17.

The quadlet of data read by the IEEE 1394 reception controller 11 isinput to an input terminal IN0 of the selector 17. The output from thefirst decryption unit 14 is input to the input terminal IN1 of theselector 17. The output from the second decryption unit 16 is input tothe input terminal IN2 of the selector 17. One of the signals input tothe input terminals IN0 to IN2 is selected according to an output of thedecryption controller 18, and is output to the IEC 61883-6 decoder 19.

The decryption controller 18 outputs a selection signal to the selector17 according to the procedure for decrypting each audio data content onthe basis of the determination signals output from the firstdetermination unit 12, the second determination unit 13, and the thirddetermination unit 15.

The IEC 61883-6 decoder 19, based on the audio data content separationinformation, which is a data removed the label from the AM824 formatdata output from the selector 17 and is input from an external device(not shown), outputs the audio data content to the parallel-serialconverter 21.

The PLL 20 and the parallel-serial converter 21 output up to 24 audiodata contents output from the IEC 61883-6 decoder 19 via a three-wireinterface from data terminals SD00 to SD23 in synchronization with acommon clock signal LRCK and a clock signal BCLK.

The IEEE 1394 receiver 10 according to the second embodiment isconfigured such that the single PLL 20 is used to transmit audio datausing a common clock. In the IEEE 1394 receiver 10, therefore, only onePLL is required for clock control. As a result, the number of terminalsof clocks can be reduced and a power consumption of the PLL can also bereduced.

FIG. 16 is a flowchart showing a process for decrypting audio datacontent.

In operation S1, the first determination unit determines whether the syparameter indicates copy-free, copy-one-generation, or copy-never. Ifthe sy parameter indicates copy-free, the process proceeds to operationS3. If the sy parameter indicates copy-one-generation or copy-never, theprocess proceeds to operation S2.

In operation S2, the second determination unit determines whether alabel in a quadlet of standard AM824 format data including a datachannel read by the IEEE 1394 reception controller 11 has a value of 4Xor any other value. If the label has a value of 4X, the process proceedsto operation S3. If the label has a value other than 4X, the processproceeds to operation S4.

In operation S3, the decryption controller outputs a selection signalfor selecting the signal at the input terminal IN0 of the selector.Then, the decryption process ends.

In operation S4, the first decryption unit decrypts the quadlet ofstandard AM824 format data including the data channel read by the IEEE1394 reception controller using the sy parameter. Then, the processproceeds to operation S5.

In operation S5, it is determined whether the label in the AM824 formatdata decrypted in operation S4 has a value of 4X or a value other than4X. If the label has a value of 4X, the process proceeds to operationS6. If the label has a value other than 4X, the process proceeds tooperation S7.

In operation S6, the decryption controller outputs a selection signalfor selecting the signal at the input terminal IN1 of the selector.Then, the decryption process ends.

In operation S7, the second decryption unit decrypts the quadlet ofstandard AM824 format data including the data channel read by the IEEE1394 reception controller using a value other than the sy parameter(e.g., copy-one-generation if the sy parameter indicates copy-never, orcopy-never if the sy parameter indicates copy-one-generation). Then, theprocess proceeds to operation S8.

In operation S8, the decryption controller outputs a selection signalfor selecting the signal at the input terminal IN2 of the selector.Then, the decryption process ends.

The process according to the flowchart shown in FIG. 16 ensures thateach audio content encrypted with copy-one-generation or copy-never canbe decrypted.

The IEEE 1394 receiver 10 according to the second embodiment receivesaudio data content of a plurality of channels through a single contentpacket. Therefore, the IEEE 1394 receiver 10 according to the secondembodiment can handle a packet having a single header portion, and theoverhead of the IEEE 1394 packet can be reduced.

Embodiments of the present invention are not limited to the first orsecond embodiment, and it is to be understood that a variety ofimprovements and modifications can be made without departing from thescope of the invention.

The first and second embodiments provide an IEEE 1394 transmitter andIEEE 1394 receiver having a three-wire interface for transmitting andreceiving audio data content of up to 24 channels. However, embodimentsof the present invention are not limited to the first or secondembodiment, and can also provide an IEEE 1394 transmitter and IEEE 1394receiver having a three-wire interface for transmitting and receivingaudio data content of a smaller number of channels such as eightchannels.

Example embodiments of the present invention have now been described inaccordance with the above advantages. It will be appreciated that theseexamples are merely illustrative of the invention. Many variations andmodifications will be apparent to those skilled in the art.

Although a few preferred embodiments of the present invention have beenshown and described, it would be appreciated by those skilled in the artthat changes may be made in these embodiments without departing from theprinciples and spirit of the invention, the scope of which is defined inthe claims and their equivalents.

1. An IEEE 1394 transmitter for transmitting a plurality of audio data contents, comprising: an audio data generator configured to sample the plurality of audio data contents sequentially to generate format data of an audio data content; and an IEEE 1394 transmission controller configured to add an IEEE 1394 header packet to the format data of the audio data content.
 2. The IEEE 1394 transmitter according to claim 1, wherein the audio data content includes a plurality of channels.
 3. The IEEE 1394 transmitter according to claim 1, further comprising: a phase-locked loop configured to generate a common clock for receiving the plurality of audio data content.
 4. The IEEE 1394 transmitter according to claim 1, further comprising: an encryption portion configured to encrypt the format data of the audio data content.
 5. The IEEE 1394 transmitter according to claim 1, further comprising: an encryption controller configured to control a level for encryption of the format data of the audio data content.
 6. The IEEE 1394 transmitter according to claim 5, wherein the IEEE 1394 transmission controller puts information relating to the level for the encryption into the IEEE 1394 header packet.
 7. The IEEE 1394 transmitter according to claim 5, wherein the level for the encryption is one selected from a group consisting of copy-free, copy-one-generation, and copy-never.
 8. The IEEE 1394 transmitter according to claim 1, further comprising: a label generator configured to generate a label for generating the format data of the audio data content.
 9. The IEEE 1394 transmitter according to claim 4, wherein the encryption portion encrypts the format data of the audio data content using 5C-DTCP protocol.
 10. An IEEE 1394 receiver for transmitting a plurality of audio data content, comprising: an IEEE 1394 reception controller configured to separates format data of an audio data content from a received IEEE 1394 packet; and an audio data content generator configured to generate a plurality of audio data content form the separated format data of an audio data content on the basis of audio data content separation information.
 11. The IEEE 1394 receiver according to claim 10, wherein the audio data content includes a plurality of channels.
 12. The IEEE 1394 receiver according to claim 10, further comprising: a phase-locked loop configured to generate a common clock for transmitting the plurality of audio data content.
 13. The IEEE 1394 receiver according to claim 10, further comprising: a first determination portion configured to determine a signal indicating a level for encryption included in the separated format data of the audio data content item.
 14. The IEEE 1394 receiver according to claim 10, further comprising: a decryption portion configured to decrypt the separated format data of the audio data content item.
 15. The IEEE 1394 receiver according to claim 10, further comprising: a second determination portion configured to determine whether a label included in the separated format data of the audio data content has a predetermined value.
 16. The IEEE 1394 receiver according to claim 10, further comprising: a plurality of decryption portions configured to decrypt the separated format data of the audio data content; and a selector portion configured to select signals from the plurality of decryption portions.
 17. An audio data content transmission method for transmitting a plurality of audio data content, comprising: separating format data of an audio data content from a received IEEE 1394 packet; generating a plurality of audio data content form the separated format data of an audio data content on the basis of audio data content separation information; and transmitting the plurality of audio data content items.
 18. The audio data content transmission method according to claim 17, wherein the audio data content includes a plurality of channels.
 19. The audio data content transmission method according to claim 17, wherein the plurality of audio data contents are output on the basis of a common clock signal generated by a phase-locked loop.
 20. The audio data content transmission method according to claim 17, further comprising: decrypting a first separated format data of audio data content into a first decrypted format data of audio data content according to a first encryption level; decrypting a second separated format data of audio data content into a second decrypted format data of audio data content according to a second encryption level; selecting from a group consisting of the first decrypted format data of the audio data content and the second decrypted format data of the audio data content; and generating the plurality of audio data contents. 